Priority-Based Access Schemes and Throughput Performance in Wireless Networks Exploiting Multibeam Antennas

Multibeam antennas (MBAs) are capable of supporting concurrent communications with multiple neighboring users in wireless networks and, thus, can improve the throughput over omnidirectional antennas and switched-beam directional antennas. The throughput performance, however, may degrade in the absence of a proper access scheme for user scheduling, and thus, collisions occur. The probability of having such collisions further increases in a multipath propagation environment, which is commonly encountered in a wireless network. Furthermore, there is an increased demand to deliver various types of data with differentiated quality and latency requirements. Thus, it is desirable to incorporate user/packet priority in the medium access control (MAC) protocol. In this paper, priority-based access schemes are proposed for wireless networks exploiting MBAs, respectively, in single-path and multipath environments. An analytical framework is then developed to analyze the node throughput performance when the proposed access scheme is used. The analytical and simulated results clearly show that, in contrast to a random-access scheme, where significant throughput degradation occurs in a multipath propagation environment, when the proposed access scheme is applied, the node throughput becomes a nondecreasing function of the offered load, and the degradation due to multipath is significantly mitigated.